Dark photon experiments [1]} such as CHARM set limits on visible and invisible decays of the dark photon. These limits are shown in the kinetic mixing-dark photon mass plane in the top panels of Fig. REF  for benchmarks (a) (left), (b) (center) and (c) (right) recast to our model parameters. Also shown are the SuperCDMS [2]} sensitivity projections for benchmarks (a) and (b) while (c) remains out of reach of SuperCDMS. In the bottom panels, we present the recast limits from the Planck experiment [3]}, [4]} for the same benchmarks in the gauge coupling \(g_X\) -dark photon mass plane. These limits pertain to the annihilation of DM to two new vector bosons followed by their decay to two \(e^+e^-\)  pairs.
The benchmarks of Table REF  satisfy all of the above constraints. There is a larger parameter space than the benchmarks of Table REF  where the experimental limits can be evaded while satisfying the relic density and producing the correct fit to the Xenon-1T excess. We exhibit those regions in the top panels of Fig. REF . The green patches show the parts of the parameter space giving the correct DM relic density for a specific choice of the dark coupling \(g_X\)  and the grey stripes indicate the regions producing the correct fit to the Xenon-1T excess.
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